bad documentation command for ubuntu installation

I was installing the mongodb CE for Ubuntu, and try to styart the service and I found that you posted the command:

```sudo apt-get install mongodb-org```

That command i snot installing the package and create the service in the project; I found the solution in:

https://askubuntu.com/questions/748789/run-mongodb-service-as-daemon-of-systemd-on-ubuntu-15-10

The correct command is: ```sudo apt-get install mongodb```

Then the entire service runs as we spect.